Thread-controlling mechanism for sewing-machines



. G. S. GATCHELL. THREAD coumoume MECHANiSM FOR SEWING MACHINES.

APPLICATION FILED MAY9,19I8.

1,342,800, Y Patented June 8, 1920.

2 SHEETSSHEET 1.

ATTORNEY G. S. GATCHELL.

THREAD CONTROLLING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED MAY 9, 191B.

' 1,342,800, Patented June 8, 1920.

2 SHEETSSHEET 2.

WITNESSES Q -W- My ATTORNEY INVENTOR UNITED STATES FATEEZNT @FFICE.

ASSIGNOR TO THE SINGER OF NEW JERSEY.

THREAD-CONTROLLING MEGEIANISM SEWING-MACHINES.

Original application filed August 10, 1917, Serial No. 185,448.

Specification of Letters Ratent.

Patented June 8, 1920.

Divided and this application filed May 9, 1918. Serial No. 233,415.

To all whom it may concern:

Be it known that I, GEORGE S. GA'rcHELL, a citizen of the United States, residing at Roselle Park, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Thread- Controlling Mechanisms for Sewing-Machines, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to needle threadcontrolling mechanism for sewing machines and has for an object to provide an im proved, simplified and efiicient mechanism for pulling needle-thread from the supply in amounts varying in accordance with the thickness of the work being stitched.

A further object of the invention is to provide a thread-controlling device which has no action upon the needle-thread during the major portion of the stitch-forming cycle and consequently does not interfere with the action of the usual take up mechanism in controlling and drawing up the needle-loops, but which acts in conjunction with a threadguide on the needle-bar as the latter nears the completion of its up stroke to determine the amount of thread pulled from the supply.

A further object of the invention is to provide the device with a manual adjustment for varying its range of automatic action.

The needle-bar of the machine is provided at its upper end with thread-guiding means comprising, in the present embodiment, a lateral arm formed with a thread-eye or, if the machine is of a multiple-needle type, with a plurality of thread-eyes arranged horizontally. Fulcrumed between its ends on a post rising from the machine-head is a thread-engaging lever formed with a socket at its forward end in which is secured a thread-stop in the form of a horizontal bar disposed closely in rear of the thread-guid ing means mounted on the needle-bar and adapted to engage the thread leading forwardly from-a take-up device mounted on top of the usual bracket-arm.

Secured to the presser-bar is an upwardly extending bracket formed with a horizontal slot in which a lateral pin is adjustably fixed. The lateral pin enters a slot in the rearwardly disposed arm of the thread-engaging lever and transmits rising-and-falling movements of the presser-bar to said lever, thereby altering the position of the thread-stop in accordance with the thickness of the work. This adjustable pin and slot connection provides for ready alteration of the range or extent of movement of the thread-stop.

The threadstop is entirely out of engagement with the needle-thread during the major portion of the stitclrforming cycle and consequently does not interfere with the action of the take-up mechanism. As the needle-bar nears the end of its up-stroke, however, the thread leading forwardly to the thread-guide at the upper end of the needlebar strikes the thread-stop and is bent about the latter; the result being that a measured amount of the needle-thread will be pulled from the supply for use during the formation of the next stitch. As the work increases or decreases in thickness, the position of the thread-stop is adjusted automatically through its connection with the presser-bar and the amount of thread pulled from the supply is varied accordingly;

In the accompanying drawings Figure 1 is a side elevation of a machine embodying the invention. Fig. 2 is a reverse side elevation of the thread-stop mechanism shown in Fig. 1. Fig. 3 is a front end elevation of the machine. Fig. 4 is a top plan view of the parts shown in Fig. 2 and Fig. 5 shows the treadle controlled presser-foot lifting means.

The improvement is illustrated as appliedto a four-needle, single-looper machine of the type disclosed in my copending application Serial No. 185,446, filed August 10, 1917, of which this application is a division. The frame of the machine is formed with a base 1 from which rises the standard 2 carrying the overhanging bracket-arm 3 ter minating in the hollow head 4. Secured to the standard 2 is the flanged rearward extremity of the hollow work-supporting arm 5. Journaled within and crosswise of the standard 2, above the horizontal plane of the workarm and crosswise of the vertical plane of the work-arm, is the main-shaft 6 carrying the pulley-wheel 7 and the usual hand-wheel, not shown.

The main-shaft is formed with a ballcrank 8 which is embraced by the lower strapped end of a pitman 9 the upper strapped end of which embraces a ball-ended crank-pin carried by the crank-arm 11 at the rear end of the needle-actuating rockshaft 12 which is journaled within the bracket arm 3 and, at its forward end, carries a crank-arm 13 connected to the reciprocating needle-bar 14 by means of the link 15. Secured to the lower end of the needlebar 14 is the needle-clamp-block 16 which, in the present instance, is socket'ed to receive four needles a arranged in a vertical plane transversely of the work-arm 5.

Mounted within the work-arm is a threadcarrying looper 17 and the usual fulling and main feeddogs 18 and 19, respectively, the looperand feed-actuating mechanisms being preferably constructed substantially in accordance with the disclosure of my said copending application. These parts, however, may be actuated in any usual or suitable manner.

The feed-dogs cooperate with a presserfoot comprising, in the present instance, a

sole-piece 20, Fig. 1, pivoted at 21 to the shank 22 secured to the lower end of the presser-bar 23 which is formed in two parallel sections offset from one another and connected to move as one bar by means of the lateral arm 24. The lower section of the presser-bar is journaled in the bushing 25 and bearing lug 26, Fig. 1, and the upper section is journaled in alined bearings formed in the bearing lug 26, Fig. 3, and in the top of the head 4. The upper section of the .presser-bar 23 carries a bracket 27 acted upon by the usual leaf spring 28. The presser-foot may be lifted by means of the usual treadle-controlled lever 29 the forward extremity of which extends under the bracket 27. The sole-piece of the presserfoot is formed with forwardly extending spaced toes 30, defining a slot within which the upturned marginal portions of material to be stitched pass toward the trimming blades 31 and stitching point.

Secured to the top of the needle-bar is a bracket 32 formed with a horizontal bar 33 having individual needle-thread eyes 34 which, it will be observed from Fig. 1', operate in a plane in advance of the head 4 of the machine-frame. The needle-thread or threads therefore may extend straight down to the guide 34 at the bottom of the head 4 without rubbing against the outer surface of said head. Cooperating with the bracket 32 to take-up or control the needle-threads during the major portion of the stitch-forming cycle are the individual. thread-engaging cams 35 each comprising a pair of spaced disks between which a stripper-blade 36 is mounted and at the outer sides of which 37 are disposed.

In order that the needle-bar may act to pull off the exact amount of thread required for the next stitch regardless of the thickness of the work, the machine is provided with means for regulating the pull-off action of the thread-eyes carried by the needlebar. Slidably mounted in a vertical aperture in the top of the head 4 is the shank of a post 38 which at its rearwardly inclined upper extremity carries a pivot-screw 39 upon which is fulcrumed the lever 40 extending in the same general direction as the bracket-arm 3. The post 38 is held in position in the head 4 by means of the set-screw 38 which may readily be loosened when it is desired to adjust the post 38 vertically, after which it may be retightened to hold the post 38 in the desired position of adjustment. The rearwardly extending arm of the lever 40 is provided with a slot 41 entered by a lateral pin 42 adjustably secured in the horizontal slot 43 formed in the bracket 44 having an apertured hub surrounding and fixed to the presser-bar 23. The forwardly extending arm of the lever 40 is apertured at its free end to receive and support a horizontal thread-engaging rod 45 having a down-turned extremity 46. The rod 45 is disposed closely in rear of the plane of reciprocation of the take-up eyes, 34, Fig. 1, and arrests the upward movement of the needle-thread-lengths extending forwardly from the thread-guiding forks 37, thereby causing the thread-eyes 34 to pull an amount of thread from the supply depending upon the elevation of the rod 45. If the work increases in thickness the rod 45 will be lowered and consequently will arrest the upward movement of the needle-thread earlier and increase the pullofl' action of the thread-guides 34, as will be clear from an inspection of Fig. 1. The pin 42 may 105 be adjusted along the slot 43 to vary its distance from the fulcrum 39 of the lever 40 and consequently vary the amplitude of movement of the lever 40 corresponding to a given amplitude of movement of the 110 presser-bar. The post 38 may also be adjusted vertically in the head 4 to vary the action of the lever 40 as may be desired.

Then the work is to be removed from the machine at the end of'a stitching operation, 115 the raising of the presser-bar causes a depression of the front end of the lever 40,

whereby the thread-stop 45 bends the needlethreads between the threadeyes 34 and the thread-guiding forks 37 and thereby pulls 12f thread through the tensions. The slackthread thus afforded is available at the start of the next stitching operation andpermits the needles to go down to -the bottom of their stroke without unthreading the needles 125 or unduly straining the needle threads. the apertured arms of a thread-guiding fork To those skilled in the art it will be obvious that the details of construction shown and described may be materially modified. without departure from the invention or 13( sacrifice of the advantages flowing therefrom.

Having thus set forth the nature of the invention, what I claim herein is 1. Thread measuring mechanism for sewing machines comprising, a needlebar, a thread-engaging device carried thereby, a work-engaging element, a slotted member operatively connected thereto, a slotted and pivotally mounted thread-engaging member with which said thread-engaging device cooperates to pull needle-thread from the supply, and a pin adjustably mounted in the slot of one of said members and entering the slot of the other of said members.

2. Thread measuring mechanism for multiple-needle sewing machines comprising, a frame including a bracket-arm, a needle bar, thread-guides carried thereby and disposed substantially in a plane transversely to the direction of reciprocation of said needle-bar, a work-engaging element, a pivoted lever connected to said work-engaging element, and a bar carried by said lever and disposed above the needle threads and immediately behind the path of movement of said thread-guides.

3. In a sewing machine, in combination, stitch-forming mechanism including a reciprocating needle-bar carrying a needle, a presser-foot, a thread-guide carried by the needle-bar, a take-up acting on the needlethread between the supply and the needlebar and a thread-stop out of engagement r with the needle-thread during the major portion of a stitch-forming cycle but adapted to be struck by the needle-thread leading from the take-up to the needle-bar, when the needle-bar nears the end of its up-stroke, whereby the needle-bar is caused to pull a measured amount of thread from the supply, and means controlled by the presserfoot'for varying the operative position of said thread-stop.

4:. In a sewing machine,- in combination,

a frame comprising a work-support and an overhanging forwardly extending bracketarm, a reciprocating needle-bar journaled in said bracket-arm, a thread-guide carried by said needle-bar adjacent the upper end of the latter, a presser-bar, a take-up device mounted on top of the bracket-arm, and a thread engaging lever pivotally carried by said bracket-arm and having its free end extended forwardly in the same general direction as the bracket-arm, said lever being operatively connected to the presser-bar and adapted to arrest the upward motion of the needlethread between the needle-bar and take-up device.

5. In a sewing machine, in combination a frame including a work-support and a forwardly extending bracket-arm terminating in a hollow head, a reciprocating needle-bar journaled in said head, a thread-guide carried by said needle-bar adjacent the upper end of the latter and moving along a vertical line in advance of said head, a presserbar and a lever controlled by the presserbar and having its free end extended forwardly in the same general direction as the bracket arm and terminating in a thread stop for engaging the needle-thread at a point closely in rear of said thread-guide as the needle-bar nears the completion of its up-stroke.

6. In a sewing machine, in combination a frame, a needle-bar journaled in said frame, a thread-guide carried by and forwardly of the needle-bar, a presser-bar, a lever having a thread stop between the paths of movement of the thread-guide and needle-bar and cooperating with said thread-guide to pull thread from the supply, a fulcrum support for said lever mounted on said frame, and an operative connection between said lever and the presser-bar.

In testimony whereof, I have signed my name to this specification.

GEORGE S. GATCHELL, 

